Chat Compactor
Generate structured summaries optimized for AI agent continuity across sessions.
Why This Exists
Human-written summaries and ad-hoc AI summaries lose critical context:
Decision rationale gets lost (why X, not Y) Dead ends get forgotten (agent re-tries failed approaches) Implicit knowledge isn't captured (file locations, naming conventions, gotchas) State is unclear (what's done, what's pending, what's blocked)
This skill produces agent-optimized handoff documents that prime the next session.
Output Format
Generate a markdown file with this structure:
Session: [Brief Title]
Date: [YYYY-MM-DD] Duration: ~[X] messages
Context Snapshot
[1-2 sentences: What project/task, what state it's in right now]
What Was Accomplished
- [Concrete outcome 1]
- [Concrete outcome 2]
Key Decisions & Rationale
| Decision | Why | Alternatives Rejected |
|----------|-----|----------------------|
| [Choice] | [Reason] | [What didn't work and why] |
Current State
- Working: [files/features that are functional]
- Broken/Blocked: [what's not working and why]
- Modified files: [list with brief note on changes]
Dead Ends (Don't Retry)
- ❌ [Approach that failed] — [why it failed]
Next Steps (Prioritized)
- [ ] [Most important next action]
- [ ] [Second priority]
Environment & Gotchas
- [Any setup notes, versions, quirks discovered]
Key Code/Commands Reference
[Only if there are non-obvious commands or snippets the next session needs]
Workflow Scan conversation for: decisions, outcomes, failures, file changes, blockers Identify the "handoff moment" — what would a fresh agent need to continue? Generate structured summary using format above Save to file: session-[topic]-[date].md in project root or /home/claude/sessions/ Compaction Triggers
Invoke this skill when:
User says: "compact", "wrap up", "save session", "summarize for next time" Context window exceeds ~50% capacity and task is ongoing Before major context switches End of debugging/implementation session Quality Criteria
Good compactions are:
Scannable: Next agent gets orientation in <30 seconds Actionable: Clear next steps, not vague summaries Defensive: Dead ends documented to prevent re-exploration Minimal: No fluff, every line earns its tokens Anti-Patterns
Avoid:
Narrative prose ("First we tried X, then Y, then Z...") Redundant context (don't repeat what's in code comments) Vague summaries ("Made good progress on the feature") Missing failure documentation (most valuable part!) Example Trigger & Response
User: "Let's wrap up, compact this session"
Agent:
Reviews conversation for key decisions, outcomes, failures Generates structured markdown per format above Saves to session-[topic]-[date].md Confirms: "Session compacted to session-auth-refactor-2025-01-06.md — ready for next time."